Parts for your 2013 Mazda 3-Tx valve

2013 Mazda 3 TX Valve — what it does and when to sort it

Based on technical sources, a TX valve is absolutely relevant and fitted on the 2013 Mazda 3. The Mazda 3 (BL series, 2009–2013) A/C system uses a thermal expansion valve (TXV) mounted at the evaporator on the firewall, not an orifice tube. This is documented in the Mazda Workshop Manual (HVAC — A/C Unit — Expansion Valve Removal/Installation), supported by the Mazda Electronic Parts Catalogue listings for the A/C expansion valve on BL-series vehicles, and mirrored by supplier catalogues such as DENSO’s aftermarket application guide and common trade databases (e.g., Mitchell1/ProDemand) that show service procedures for the TXV on the 2013 model.

The TX valve’s job is to meter R‑134a into the evaporator so the cabin cools quickly and consistently without icing. It reacts to evaporator outlet temperature (superheat), trimming flow so the evaporator uses just the right amount of refrigerant. When it’s working well, you get steady vent temperatures, good performance at idle, and a happy compressor. When it’s cactus, you can see warm air at the lights, frosty pipes, noisy cycling, or pressure readings that are all over the shop. Because it’s a precision metering device, dirt, moisture, or wear can make it stick open or closed, or clog partly.

• Typical symptoms: poor cooling at idle, evaporator freeze-up, fluctuating vent temps, or high low‑side/low high‑side gauge readings.
• It’s not a routine “service” item, but it’s commonly replaced when there are performance faults or the system’s been contaminated.
• Any time the system is opened, plan on new O‑rings and replacing the receiver/drier or desiccant bag (often integrated with the condenser on late-model Mazdas).
• Use the Mazda-specified PAG oil and recharge to the exact sticker charge under the bonnet.
• Torque line fittings to workshop spec and leak-test before recharging.

Replacement is straightforward for a licensed A/C technician: safely recover the gas, remove the firewall line block, swap the TXV and O‑rings, evacuate the system for adequate time, then charge by weight. In Australia, this work must be done by an ARCtick‑licensed tech and in NZ by a suitably certified refrigerant handler. If the system’s seen compressor failure or moisture ingress, budget for a condenser/drier and a thorough flush, otherwise a new TX valve can be short‑lived.

Popular questions

Does a 2013 Mazda 3 use a TX valve or an orifice tube?
It uses a thermal expansion valve (TXV) at the evaporator inlet on the firewall. This configuration is shown in the Mazda Workshop Manual and parts catalogues for BL‑series cars. An orifice tube isn’t used on this model.

What are the tell‑tale signs the TX valve is failing on a Mazda 3?
Look for weak cooling at idle, vent temps that swing hot‑cold, frosting at the evaporator/lines, or odd gauge readings (low low‑side with normal high‑side for a stuck/plugged TXV). A qualified tech will confirm with pressure diagnostics and temperature measurements.

Should the drier be replaced when changing the TX valve?
Yes, best practice is to replace the receiver/drier or desiccant bag whenever the system is opened, along with O‑rings. Many late Mazdas use a condenser with an integrated drier, so the desiccant service kit or condenser may be required, depending on build.